Bioinspired staggered-array structure design for flexible batteries

Abstract

As a key component to enable future flexible and wearable electronics, flexible batteries have received great attention in recent years. While much progress has been achieved, few of these batteries have high bendability, high bulk volumetric energy density and high areal energy density simultaneously. Here, inspired by the microstructures of bone and nacre, a novel staggered-array structure composed of thin sub-cells and soft adhesives is reported for flexible batteries. An analytic model, without any parameter fitting, is presented to study the mechanical behavior of the structure bent on a cylinder, which accurately captures the axial strains of the thin sub-cells and exhibits the effects of different parameters on strain reduction. Based on the results of the developed model, a flexible lithium-ion battery is prepared as a demonstration, which simultaneously exhibits high bendability, high bulk volumetric energy density and high areal energy density. Owing to the thin soft adhesives, the interactions among thin sub-cells are substantially reduced, and the bulk volumetric energy density of the battery reaches as high as 92.3% of that of conventional batteries, indicating tremendous potential of the staggered-array structure for applications in flexible and wearable electronics.